Fluid impact coupling combined with clutch



Oct.' 17, 1944.

4 H. NUTT EI'AL FLUID IMPACT COUPLING. COMBINED WITH CLUTCH OriginalFiled Jan. 4, 1941 Patented Oct. 17, 1944 UNITED STATES PATENT orsicsFLUID IMPACT COUPLING COMBINED I wrrn'owrcn Harold Nutt, Chicago, andmama L. Smirl, Bellwood, Ill., assignors to Borg-=Warner Corporation,Chicago, 111., a corporation of Illinois Original application January 4,1941, Serial No.

373,201. Divided and this 30, 1942, Serial No. 436,852

(Cl. nag-3.2) f

16 Claims.

This invention relates to a fluid impact coupling combined with aclutch. This application is a division of I our prior application Serial.No. 373,201 which was filed January 4, 1941.

The principal object of this invention is to for connecting the drivingand driven elements of a hydro-dynamic coupling together, the clutchbeing releasable at the option of the operator by the pressure of thefluid within the coupling.

These and other objects and features of this invention will becomeapparent from the following detailed description when taken togetherwith the accompanying drawing wherein:

Fig. 1 is a schematic, section taken through a hydrodynamic torqueconverter and its positive lock-up clutch and the fluid circuit there-'for; and

Fig. 2 is a fragmentary section through the positive clutch taken alongline 2-2 of Fig. 1.

In the embodiment of this invention chosen for illustration, a driveshaft I0 is connected at one end to an engine (not shown) and at theother end to a hydrodynamic torque converter which modifies the torqueof the engine as it is impressed upon a driven shaft l2. Torqueconverter H is comprised of a housing |3 driven from drive shaft l0 anddriving a vaned pump element It. Hydraulically associated with pumpelement I4 is a varied turbine element 15 which is directly connected todriven shaft 12, and a vaned stator element l6 which is connected to afixed transmission casing I! through a one-way brake l8. Under normalcircumstances the rotation of pump element l4 energizes a fluid which ispumped under pressure into housing I3 and the energized fluid thentransmits its energy to turbine element i5 either at increased torque orat the same torque. depending upon whether stator element I6 isstationary or'is rotating in the same direction as pump element l4.

Theoretically, when torque converter ceases to convert torque andbecomes a hydraulic coupling, a one-to-one drive should exist betweendrive shaft l0 and driven shaft |2. Practically, however, there isconsiderable slip between pump element l4. and turbine element I! sothat although no multiplication in torque occurs,the speed ratio betweendrive shaft l0 and driven shaft II is greater than unity. This of courseapplication March means that the efficiency of the drive is less than100%, and to increase the efllciency a positive 1 clutch I9 is employed.

Clutch I8 is comprised of an axially extending drum 20 secured to rotatewith housing l3 and drive shaft ill, a carrier 2| secured to rotate withdriven shaft l2, and one or more pawls 22 slidably mounted in carrier 2|and adapted to couple drum 20 to carrier-2|. In the form shown in Fig.2, drum 20 is provided with a plurality of I slots 23 and carrier 2| isprovided with radially extending bores 24 with pawls 22 slidablyretained in bores 24. Said pawls 22 fit closely in their respectivebores 24 so as to function as pistons.

A passageway 25 passes directly through shaft I2 and connects oppositebores 24 so that such opposed bores are hydraulically in communicationwith one another. The outer end 26 of each pawl 22 is formed with a'camsurface 21 which serves to eject paw1 22 from slot 23 until drum 20 andcarrier 2| are rotating at substantially the same speed.

Pawls 22 are subject to centrifugal force when carrier 2| is rotatingand accordingly will normally tend to move radially outwardly so as toeffect a connection between carrier 2| and drum 20. This radial outwardmovement is restrained is attained. For reasons of economy it is desirable to lock up converter II at the earliest possible time and thereforespring 28 is such that it will permit engagement of pawl 22 with slot 23at speeds wherein torque conversion in converter II is still possible.Under certain circumstances, the added torque increase is desirable andif it should be desired after pawls 22 are in engagement with slot 23some means must be provided for withdrawing the pawls in order to makethe torque converter effective. This means will now be described. 45

It will be observed that a sleeve 29 is secured to pump elements l4 soas to be rotatable therewith. Said sleeve 'drives a pair of gears 30, 3|which in turn drive a pump 32. Said pump draws fluid from the sump ofthe transmission (not shown) at the inlet side 23 of the pump andtransmits the fiuid under pressure through a conduit v34 to a valveblock 35. The pressure in conduit 34 is regulated by means of a pressureregulating valve 38 which by-passes the fluid back into intakepassageway 38 when the fluid pressure becomes too high. Conduit 34 con-fnects with a conduit "31 in valve block 35 which.

an opening 39 betweenstator support 40 and sleeve 28 into housing I3.f'luid'under pressure.

v ing passageway 4 i.

is also conductedfrom passageway 31 through a branch conduit 4| and aconnecting conduit 42 in shaft 12 to passageway 25. The passage of fluidinto conduit 4| is controlled by means of a valve 43 which is normahybiased to open position by a spring 44 and may be moved to a closedposition as shown in Fig. 1 by means of a lever 45 controlled by theoperator. When valve 43 is in the position shown, passageway .4l isvented to the left (Fig. 1) of valve blocksure. Thus as long as thepressure on both sides of the pawls is balanced they are subject only tocentrifugal force as modified by spring 28.

The pressure within the housing remains constant so long as drive shaftit is rotating, but the pressure on the inside of the pawls 22 may becontrolled by'valve 43. Assuming that clutch mg drive and drivenelements, a source of fluid under pressure, fluid operated means fortransmitting torque between the elements, additional means controlled bythe speed of one of said elements for transmitting torque between saidelements, said additional means being biased to disengaged position bythe fluid under pressure, and means opposing the bias to permit thespeed control to become effective.

Ill"

It is engaged and that the operator wishes to disengage the clutch so asto drive through the converter ll, all that he need do is to rotateleverlii clockwise as viewed in Fig. 1, thereby moving pawl tit to theposition shown and vent- The pressure on the inside of pawls 22immediately drops to zero and the previously balanced condition of thepawl becomes unbalanced in favor of retracting pawls 22. The pressure ofthe fluid within housing is therefore acts upon the outside of pawls 22and, assisted by spring 28;forces pawls 22 radially inwardly to areleased position. It is contemplated of course that torque shall beremoved from clutch is at 'the time conduit 65 is vented as described inthe above mentioned prior application. It is further contemplated thatabove the speed at which torque converter H is no longer effective toconvert torque the pressure within housing 13 will be insuflicient toovercome the centrifugal force developed in the pawls and the pawlstherefore will not be retracted.

It is understood that the foregoing descriptionis merely illustrative ofa preferred embodiment of. the invention and that the scope of theinvention therefore is not to be limited thereto but is to be determinedby the appended claims. Thus it is immaterial insofar. as this invention1 is concerned whether the pawls move radially,

axially or obliquely, and it is likewise immaterial whether the pistonportion acts directly upon the pawl or upon a pressure plate of afridtion clutch.

We claim: 1. A torque transmitting mechanismcomprising drive and drivenelements, a source of fluid under pressure, fluid operated means fortransmitting torque between the elements, additional means controlled bythe speed of one of said elements for transmitting torque between saidelemeats, said additional means having a surface exposed to the fluidunder pressure, and means for substantially balancing the pressureexerted 3. A torque transmitting mechanism'compris- -ing drive anddriven elements, a source of fluid under pressure, fluid operated meansfor transmitting torque between the elements, a clutch' for connectingsaid elements to bypass the fluid operated means, means for operatingsaid clutch and being speed-responsiveto engage the clutch, said lastnamed means includingfa piston connected with the clutch and having oneside exposed to the fluid under pressure, and means for balancing atleast a portion of the pressure exerted upon the piston to permit theclutch to be operated in response to speed.

4. A torque transmitting mechanism comprising drive and driven elements,a source of fluid under pressure, fluid operated means for transmittingtorque between the elements, additional means controlled by the speed ofone of said elements for transmitting torque between said elements, saidadditional means having a surface exposed to the fluid under pressure,and manually operated means for selectively balancing the pressureexerted by the fluid on said surface to per-. mit said additional meansto be speed controlled or for removing the balancing pressure toestablish an unbalanced condition in favor of disconnecting saidadditional means over a predetermined range oi speeds of said one ofsaid elements.

5. A torque transmitting mechanism comprising drive and driven elements,a source of fluid v responsive to engage the clutch, said last named bythefluid to permit the speed controlled means 3 to become eflective.

2. A torque transmitting mechanism comprismeans including differentialoperating means for the clutch having one surface exposed to thepressure within the chamber whereby to bias the clutch to inoperativeposition and means for sub stantially balancing the pressure to permitthe clutch to be operated in response to speed.

6. A torque transmitting device comprising drive and driven elements, asource of fluid under pressure, fluid operated means for transmittingtorque between the elements, a' clutch for transmitting torque betweensaid elements, said clutch having a surface exposed to the fluid underpressure so as to be biased to disengaged position, and means forovercoming the disengaging bias to engage the clutch.

7. A torque transmitting device comprising drive and driven elements, asource of fluid under pressure, fluid operated means for transmittingtorque between the elements, a clutch for transmitting torque betweensaid elements, said clutch having a surface exposed to the fluid runderpressure so as to be biased to disengaged position, and means controlledby the speed of one of the elements for overcoming the disengaging biasto '7, and manually operated over-control means for rendering thespeed-controlled means ineffective engage the clutch.

9. A torque transmitting device comprising drive and driven elements, asource of fluid under pressure,,a rotatable housing normally filled withfluid under pressure, means connecting the housing with the drivingelement, a vaned pump element in said housing, aid driven thereby, avaned rotor connected to the driven element and coupled to the pumpelement through the fluid, a clutch for coupling the pump and rotorindependently or the fluid, pressure differential operating means forthe clutch having one surface exposed to the pressure within thechamber, whereby to supply releasing pressure for the clutch, and meanscontrolled by the speed of one of the first mentioned elements forengaging the clutch.

10. A torque-transmitting device comprising drive and driven elements, asource of fluid under pressure, fluid-operated means for transmittintorque between the elements, a clutch for transmitting torque betweensaid elements, said clutch comprising a slotted member on the driveelement, substantially radial bores in the driven element, pistons inthe bores. Said Pistons having extensions engageable with the slots, aconduit connecting said bores, said extensions being exposed to thefluid under pressure so as to be biased to ,disengaged'position, andmeans for establish-1 ing sufficiently great pressure in the connectingconduit substantially to balance the disengaging bias and condition theclutch for engagement.

11. A torque-transmitting device comprising drive ancl'driven elements,a source of fluid under pressure, fluid-operated means for transmittingtorque betweeng the elements, a clutch for transmitting torque betweensaid elements, said clutch comprisingv a slotted member on the driveelement, substantially radial bores in the driven element, pistons inthe bores, said pistons having extensions engageable with the slots, aconduit connecting said b'ores, resilient means in tension in the boresconnecting the pistons to retract said pistons, said extensions beingexposed to'the fluid under pressure so as to be biased in disengagedposition, and means for establishing sufliciently great pressure in theconnecting conduit substantially to balance the disengaging bias tocondition the clutch for engagement. I

12. A torque-transmitting device comprising drive and driven elements, acontainer, means for supplying fluidunder pressure to the container, avaned driving element in the container and connected to the driveelement, a cooperating vaned rotor likewise in the container andconnected-to the driven element, said vaned element and rotor comprisingfluid-operated means for transmitting torque between the drive anddriven elements, a clutch for transmitting torque between said elements,said clutch comprising a slotted member on the drive element,substantially radial bores in the drivenelement, said radial borescommunicating with the fluid under pressure in the container, pistons inthe bores, said pistons having extensions engageable with the slots, aconduit connecting said bores, said extensions being exposed to thefluid under pressure so as to be biased to disengaged position, andmeans for admitting fluid from'the source supplying the container to theinner e pistons substantially to balance the disengaging nds oi theunder pressure, a hydrodynamic coupling device connected withsaidlsource of fluid and transmitting torque between, said drive anddriven elements, a clutch for completing a power train between saiddrive and driven elements independently of saidhydrodynamic-device,means for opcrating said clutch and comprising a piston disposed in asubstantially radially extending bore in one of said elements wherebythe piston is movable outwardly under centrifugal force for engagingsaid clutch, the outer end, of said piston being exposed to the fluidunder pressure in said hydrodynamic device so as to be biasedto'clutchdisengaging position, and means for providing a pressure on the innerend of said piston'tor sub stantially balancing the pressure on itsouter end to permit the piston to move outwardly under centrifugal forcefor engaging the clutch.

15. A torque transmitting mechanism compris ing drive and drivenelements, a source of fluid under pressure, a hydrodynamic couplingdevice for transmitting torque between the elements and comprising afluid chamber connected with said source of fluid, a clutch fortransmitting torque between said elements, means for operating saidclutch comprising a plurality of pistons disposed in substantiallyradial bores in said driven element and movable outwardly undercentrifugal force to engage the clutch, said pistons being disposed withtheir outer ends exposed to the fluid under pressure in said chamber soas to be biased v comprising a fluid chamber connected with said sourceof fluid; a clutch for transmitting torque between said elements; meansfor engaging said clutch and comprising a pair of pistons disposed insubstantially radial, oppositely extending bore! in said driven elementwhereby the pistons are movable outwardly under centrifugal force toen-' gage the clutch; a conduit connecting both bores.

resilient means in tension in the bores con-- necting said pistons toretract the pistons; the outer ends of said pistons being incommunication with said chamber and thereby being exposed to the fluidunder pressure therein so as to be biased to clutch disengagingposition; and means including a valve for admitting fluid from saidfluid pressure source to said bores and the inner ends of. said pistonsto substantially balant bias and condition. the clutch for engagement,76

the pressure on the outer ends of the pistor whereby the pistons maymoveunder centritug iorce to clutch engaging position.

HAROLD iw'rr. RICHARD L. SMIRL as described

